The identification and use of reinforcing stimuli is a critical component in the education and treatment of individuals with severe and profound cognitive impairments. Over the past twenty years, researchers have developed sophisticated means of identifying reinforcers for these individuals. This literature also reveals that reinforcer value changes over time. Decrements in reinforcer effectiveness can result in the deterioration of interventions that are dependent on positive reinforcement, making it important to understand the variables that can influence the value and durability of reinforcers. Observations from our pilot research suggest that (1) the inclusion of stimuli as reinforcers in response-reinforcer contigencies can enhance or sustain the value of stimuli, and (2) gradual increases in the amount of effort required to earn a reinforcer can enhance its value relative to stimuli that are earned with less effort. This set of observations suggests that response-reinforcer contingency arrangements can be used to enhance the value of reinforcers, sustain the value of reinforcers, and possibly, to establish neutral stimuli as new reinforcers. These propositions will be tested in the present study. In Experiment 1, the effects of contingent delivery, [unreadable] contingent delivery with gradually increasing response requirements, and noncontingent delivery of stimuli on changes in the value of reinforcing stimuli will be evaluated in an effort to replicate our pilot findings. The aims of Experiment 2 are to compare the enhancement of reinforcer potency through these means with two conventional alternative means of enhancing stimulus value (respondent conditioning of neutral stimuli through stimulus-stimulus pairing and reinforced engagement of neutral stimuli). Finally, the utility of these methods in establishing therapeutically effective reinforcers will be evaluated by determining whether stimuli that are initially ineffective in displacing severe destructive behavior (e.g., self-injury) in the target population, can be used effectively in this manner following exposure to the value enhancement procedures. [unreadable] [unreadable]